The following technologies are known for creating a molecular model which is a physical representation of a molecular structure:
(1) Hinomoto Synthetic Resin Model (Japanese Utility Model Laid-Open No. H3-86378).
The feature of the Hinomoto Synthetic Resin model (hereafter “Hinomoto model”) resides in the fact that a distance between the atoms is determined by having equivalent spherical (polyhedral) atoms and changing the length of the bonding rod according to the types of bond. In this method, since there are multiple types of bond based on the types of atom, there is also a need for preparing multiple lengths of bonding rod. However, even if all such components are prepared, a user has to refer to charts every so often for assembling the components to form a molecular model, resulting in tedious labor.
A further serious problem involved in this technology resides in a theoretical aspect in which the Hinomoto model cannot accurately express a distance between any combination of atoms. For example, when considering a single bond distance between two carbon atoms C, the measured distance value when both atoms are single bonded is 1.527 Å, and the measured distance value when both atoms are triple bonded is 1.377 Å, resulting in a 10% difference. However, this model expresses the distance by using only one bonding rod. For a molecule model for a well known atomic structure can be constructed by adjusting the length of the bonding rods according to the distance between the atoms, however, such manual construction requires a great amount of labor. Further, this model cannot be applied to those molecules with unknown atomic structure. Therefore, as far as the accuracy is concerned, the application of this conventional model is limited.
(2) Bruce Heywood Nicholson Model (U.S. Pat. No. 3,841,001).
The feature of Bruce Heywood Nichoson model (hereafter “Bruce model”) is that spherical atoms are designed one-third (⅓) of the van der Waals radius and are connected to the rod portion as one unit. The distance between the atoms is a sum of radiuses of the two spheres and a portion of the rod not inserted in the two spheres. The inventor of this model emphasizes that this model achieves high accuracy with use of the van der Waals radius. However, the actual distance between the atoms is based on the total length of the radiuses from the spheres and the length of the bonding rod, thus, the exclusive use of the van der Waals radius does not hold any significance. To put is more strongly, the radiuses of the spheres can be set in any way as long as the total length of those radiuses and the length of the bonding rod can be expressed accurately.
The above patent shows this problem clearly because it discloses that the differences in distance between varying atoms is determined by the depths of sockets. This means that the bonding distance between various pairs of atoms is determined by various combinations of the radial spheres and bonding rod lengths. Consequently, the Bruce model is more complicated than the Hinomoto model noted above, and is applicable to further limited pairs of atoms.
Further, another detailed yet important point is that the van der Waals radius of the carbon atoms has not been actually measured, and thus, there is no measured value. Although the covalent bond radius of the carbon is known, it cannot be incorporated as van der Waals radius since the definition is different. Either way, the Bruce model cannot accommodate the measured values from either van der Waals radius or covalent bond radius.
As mentioned above with reference to examples of conventional representing model, the reason why there has not yet been any simple and accurate configuration of molecular structure models, in spite of the progress in the chemistry, is due to the following problems:
(1) First, there is a problem because of making all the spherical atoms identical size without considering their differences in the valence state. In the Hinomoto model, all of the atoms are made identical size to one another so that the accuracy is determined only by the difference in the bonding rod lengths. However, ignoring the valence state even in the bonding distance between a pair of same atoms will result in wide unevenness of the distance and confusion as to which bonding rod length should be used, thereby making it impossible to build a unique and accurate model.
In the Bruce model, the atoms are made identical by using the van der Waals radius per every element without considering the valence state. This idea may seem superior to the Hinomoto model, however, it can only express the accuracy with respect to extremely limited pairs of atoms. Further, the only difference in the Bruce model is that the bonding rod length in the Hinomoto model is replaced by the total length of the spheres and rod, thus, the actual problem has yet to be solved. As a result, similar to the Hinomoto model, the Bruce model cannot uniquely and accurately express various pairs of atoms.
Further, since there is a basic need to simplify the concept of the molecular structure model, there appears motivation of trying to converge any carbon state into one numeric value by not only model producers but also specialized chemists in this field as well. Since the bonding distances vary between various pairs of atoms actually exist, the reason why a consistent and applicable model has not yet existed is mainly because of the problems noted in (1). For example, carbon C can comprise eight different types when the valence state is taken into consideration, where four of them shown in FIG. 1(a) which generally exist. Also, the abbreviated reference symbol and formal reference notations of the types of bond used in the present specifications and drawings are shown in FIG. 1(b).
In each of such different types, the individual electron orbital state differs, thus, the expressed sizes should differ as well. The conventional idea was that such differences can be negligible, however, it will limit the accuracy, and therefore, cannot build a consistent and universal model.
(2) The next problem is the lack of consideration on the types of bond, namely, the failure to express the lengths of the single bond, double bond, and triple bond separately. According to the theory of molecular orbit, the single bond is distinguished by having a δ bond, the double bond is distinguished by having a δ bond and a π bond overlapping with each other, and the triple bond is distinguished by having a δ bond and two π bonds overlapping with each other. Although various pairs of atoms exist, a detailed study as to whether such bond lengths share any commonality or not has never been conducted as of today. At most, the study probably goes as far as finding out that the bonding distance between a pair of identical atoms become longer in the order of triple bond, double bond, and single bond. As for the numeric values regarding the bond length, the covalent bond radiuses of the single bond, double bond, and triple bond are respectively determined.
With respect to the conventional models, the Hinomoto model makes distinction regarding the forms, however, it does not mention anything about the length of the bonding rod. In the Bruce model, neither form nor length is taken into consideration. The covalent bond radiuses based on the types of bond by Pauling was thought to have a far superior application value, however, in the valence state such as (═C<), for example, the carbon atoms cannot be expressed as spheres. Further, their numeric values are insufficient in expressing the accuracy of the bonding distance between the pairs of atoms in various valence states. Therefore, the two problems noted above are said to be the main cause of why a simple, general, unique, and accurate molecular structure models have not yet existed.